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.TH SHM.H 3HEAD "Sep 10, 2004"
.SH NAME
shm.h, shm \-  shared memory facility
.SH SYNOPSIS
.LP
.nf
#include <\fBsys/shm.h\fR>
.fi

.SH DESCRIPTION
.sp
.LP
The <\fBsys/shm.h\fR> header defines the following symbolic constants:
.sp
.ne 2
.na
\fB\fBSHM_RDONLY\fR\fR
.ad
.RS 14n
attach read-only (else read-write)
.RE

.sp
.ne 2
.na
\fB\fBSHM_RND\fR\fR
.ad
.RS 14n
round attach address to SHMLBA
.RE

.sp
.LP
The <\fBsys/shm.h\fR> header defines the following symbolic value:
.sp
.ne 2
.na
\fB\fBSHMLBA\fR\fR
.ad
.RS 10n
segment low boundary address multiple
.RE

.sp
.LP
The following data types are defined through \fBtypedef\fR:
.sp
.ne 2
.na
\fB\fBshmatt_t\fR\fR
.ad
.RS 12n
Unsigned integer used for the number of current attaches that must be able to
store values at least as large as a type unsigned short.
.RE

.sp
.LP
The \fBshmid_ds\fR structure contains the following members:
.sp
.in +2
.nf
struct ipc_perm shm_perm       /* operation permission structure */
size_t          shm_segsz      /* size of segment in bytes */
pid_t           shm_lpid       /* process ID of last shared memory
                                  operation */
pid_t           shm_cpid       /* process ID of creator */
shmatt_t        shm_nattch     /* number of current attaches */
time_t          shm_atime      /* time of last \fBshmat()\fR */
time_t          shm_dtime      /* time of last \fBshmdt()\fR */
time_t          shm_ctime      /* time of last change by \fBshmctl()\fR */
.fi
.in -2

.sp
.LP
The \fBpid_t\fR, \fBtime_t\fR, \fBkey_t\fR, and \fBsize_t\fR types are defined
as described in <\fBsys/types.h\fR>. See \fBtypes.h\fR(3HEAD).
.sp
.LP
In addition, all of the symbols from <\fBsys/ipc.h\fR> are defined when this
header is included.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
.TE

.SH SEE ALSO
.sp
.LP
.BR shmctl (2),
.BR shmget (2),
.BR shmop (2),
.BR ipc.h (3HEAD),
.BR types.h (3HEAD),
.BR attributes (7),
.BR standards (7)
